End-dressing for tubular casings

ABSTRACT

Improved strands of sausage casings having their filling ends dressed have fewer failures as a result of loose tab-ends. Residual casing material remaining on the end of the casing from severing from other casing material is made to cling to the terminal end by the application of compressive force and heat in a sufficient amount to avoid fusion of the casing material.

This is a continuation of Ser. No. 559,165, filed Dec. 7, 1983.

BACKGROUND OF THE INVENTION

The present invention relates to improved shirred or sheated strands oftubular food casings and methods of manufacture. More particularly, thepresent invention relates to sausage or meat castings having improvedend-dressings which substantially reduce or eliminate filling equipmentjamming due to interference by residual casing material or loosetab-ends.

Food casings, such as those made of regenerated cellulose and collagenhave been widely used for a number of years in processing frankfurters,sausages, bologna, etc. For instance, the basic process formanufacturing small diameter casings of regenerated cellulose is knownas the "viscose process" and is described in such patents as U.S. Pat.Nos. 2,999,756 and 3,835,113. Essentially, viscose is extruded throughan annular die into a coagulating bath to form a tubular casing. Theregenerated gel is impregnated with a plasticizer, dried and wound intoflat reelstock. For convenience in handling and in filling such foodcasings, they are shirred on high-speed shirring machines, like thosedescribed in U.S. Pat. Nos. 2,010,626; 2,583,654; 2,722,714; 2,722,715;2,723,201; and 3,451,827. In the shirring process, lengths of from 40 to200 feet of casing are compacted into pleated strands of a few inches,e.g., 4-30 inches at a rate of 10 to 15 ft./sec.

As part of the shirring process, the strands must be severed, forexample, from continuous reelstock from which they originated. Most ofthe methods for severing shirred artificial sausage casings routinelyresult in the formation of a loose or unshirred tab-like piece ofresidual casing material which remains at the horn insertion (tab) endof the strand. In the case of manual filling of sausage casings, thepresence of such a loose tab at the horn insertion end can be rectifiedby the operator's manual dexterity and does not present a major problem.However, in high-speed, highly automated filling operations, thepresence of a loose tab-end on the horn insertion end of a strand canhave more major consequences. For example, a loose tab-end caninterefere with the proper fitting of a strand onto the stuffing horn ofa high-speed filling machine becoming entangled as the horn is insertedautomatically into the strand. Under such circumstances, the strand candeshirr from both the filling and horn insertion end causing the processto jam, discharging meat into the filling station work area which meanslost meat emulsion, as well as lost production output due to downtime.Accordingly, there is a need for improved tubular strands of foodcasings and methods of manufacture wherein the casings haveend-dressings, which eliminate jamming and fouling when used inconjunction with high-speed automated filling equipment.

The present invention provides for more dependable end-dressedsausage/meat casings through the elimination of interfering residualcasing material or loose tab-ends formed as by-products of shirringoperations. By ironing down the tab-ends formed on at least one end of asevered shirred casing by application of heat to the terminal edge ofthe side-walls of a strand under controlled temperatures, the loose tabwill cling and become an integral part of the casing side-wall. But,because the tab and adjacent casing pleats are not fused by the ironingprocess the casing will completely deshirr in a normal manner duringfilling operations as meat emulsion is forced into the strand therebyavoiding loss or waste of casing material.

Accordingly, it is a principal object of the present invention toprovide more dependable, fail-safe strands of tubular food casing whichare compatible for use on high-speed automated filling equipment.

It is a further object of the present invention to provide a method formaking improved end-dressings on artificial sausage casings.

These and other objects, features and advantages of the presentinvention will become more apparent from the following more detaileddescriptions.

SUMMARY OF THE INVENTION

The present invention provides for improved sausage casings having anend-dressing on the casing's tab (horn insertion) end which will notimpede or interfere with the normal operation of automated fillingequipment. Pleated casings coming off shirring machinery having residualcasing material in the form of a loose tab-end usually resulting fromthe severing of strands are dressed by compressing the residual materialagainst the terminal edge of the strand while heating at a temperaturesufficient to cause the residual material to cling to the strand withoutcausing fusion or degradation of the tab or pleated casing material. Thetab is ironed against the side-walls of the terminal edge of the strand,and therefore, pay-out of the strand during filling operations is notimpeded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of shirred strand of casing with loosetab-end.

FIG. 2 is an end view of the casing of FIG. 1 with loose tab-end.

FIG. 3 is an enlarged sectional view of end-dressed casing of thepresent invention.

FIG. 4 is an end view of the casing with an end-dressing.

FIG. 5 is a side sectional view of the end-dressed casing of FIG. 4.

FIG. 6 is a side cross-sectional view of the strand inserted into anend-dressing unit.

DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to FIGS. 1 and 2, there is illustrated a strand of tubularcasing 1, having a central opening or bore 7. The horn insertionterminal end of the strand has an edge 5 consisting of terminal pleatsor folds of casing material. FIGS. 1 and 2 show the casing strandwithout an end-dressing after being severed from a longer shirred strandor flat reelstock, which strand may have been doffed and transferred toa strand handler of a shirring machine, and ready to be dressed. Hence,casing 1 has residual casing material in the form of a loose tab-end 3remaining at the horn insertion terminal end as a by-product of beingseparated from other casing material.

The improved end-dressed shirred tubular casings and methods ofmanufacture as described herein are applicable to both edible andnon-edible types. Typically, such casings are formed from regeneratedcellulose or collagen of the kind used in the preparation of sausages,including frankfurters, etc. The concepts embodied herein are alsoapplicable to virtually any shirred casing material, such as tubularfilms of amylose, starch, polyvinyl alcohol, alginates, cellulosederivatives, gelatin, casein, or plastic films like polystyrene,polyvinyl chloride, polyvinylidene chloride, polyolefins likepolyethylene, polypropylene and polyesters, nylons, etc., wherebysevering the casing material leads to the formation of undesiredresidual material at the end of the casing. In addition to casingshaving end-dressings on the tab end, i.e. the end of the strand to beinserted onto the stuffing horn of a filling machine, the invention alsocontemplates end-dressed strands having casing closures at the opposingend of the strand to prevent discharge of meat emulsion from the strandduring filling operations.

The objective of eliminating the problem of loose tab-end 3 from thehorn insertion end of the strand is achieved by compressing the residualcasing material against the terminal edge of the casing wall 5 whereby adressed-end is made without obstructing the central opening 7. Theresidual material is essentially ironed to the terminal edge of thecasing by moderate compressive force applied against that end of thestrand. The compressive force is applied in conjunction with sufficientheat to the terminal edge to cause the loose tab-end to cling to theterminal pleats without coming apart when the compressive force isremoved. Likewise, when the dressed-end reaches ambient temperatureconditions the ironed tab will continue to cling to the terminal pleats,but will release from the terminal pleats during filling. The elevatedtemperatures and exposure time should be preferably controlled to avoidconditions which will produce an adhering, adhesive or sticking affectof the tab-end to the terminal pleats of the strand as a result ofeither fusion, melting or degrading of the casing material. Atemperature sufficient to produce a clinging affect is most advantageousin order not to weaken the casing wall and avoid rupturing and loss ofmeat emulsion during filling operations. Similarly, fusion or melting ofthe tab-end and terminal pleats can impede casing pay-out during fillingreducing the amount of casing available per strand.

As previously indicated, the temperatures employed in making theend-dressing of the present invention should be controlled so as toproduce a clinging affect. The actual temperatures utilized to achievethat affect are dependent on the particular casing material.Nevertheless, temperatures in the range of between about 150° and about200° F. were found to be suitable in a number of instances. However,temperatures below 150° F. and above 200° F. may also be utilizedprovided the exposure time is appropriately adjusted. In this regard, itwas found at the above temperatures the exposure time will range fromabout two to about four seconds. These intervals can, of course, beincreased by adjusting the temperature downwardly or decreased byincreasing the temperature. Thus, for example, it is possible to form anend-dressing on regenerated cellulose casings at temperatures of morethan 200° F. provided the exposure time is reduced, for example, to twoseconds or less. Accordingly, the determination of appropriatetemperature and time intervals can be ascertained through the exerciseof ordinary skill.

The end-dressings of the present invention can be made, for example,utilizing a heating unit 11 illustrated in FIG. 6, comprising a heatingelement 13 with electrical leads 15 to an appropriate temperaturecontrol thermostat (not shown). Heating element 13 conducts heat to adie surface 19 which has a inside diameter sufficient to circumscribethe edge of the shirred strand. The die surface may also include arounded, convex-like surface centering support 17 which aids incentering and feeding the edge of the casing with loose tab-end 3 flushagainst the heated die surface 19. Support 17 fits inside centralopening 7 of casing 1 to assure residual casing material is ironedagainst the strand without protruding into the central opening to becomeentangled on the stuffing horn of a filling machine when insertedthereon.

Heating unit 11 is shown equipped with a resistance-type heating element13 which conducts heat to die surface 19. However, the invention alsocontemplates other means for transferring heat to the edge of thecasing, including convection and radiation means, such as by use ofinfra-red rays, forced hot air or circulating a liquid heating medium tothe die, e.g. oil.

The finished end-dressed casing according to the present invention isillustrated in FIGS. 3-5. The loose tab-end is shown ironed at 9 to theterminal end of the casing 1 clinging to the edge of the side-wall. Thedressed-end 22 may have a generally glazed appearance 21. However, thecolor of the heated casing material does not vary from the balance ofthe strand indicating the absence of degradation. Correspondingly, thetab-end and adjacent pleats can be deshirred by hand indicating theabsence of any fusion of the tab-end to the end pleats of the strand toone another thereby assuring proper pay-out of the casing duringfilling.

The present invention contemplates forming the end-dressings on shirredstrands of casing by means of automated equipment. For instance,automated high-speed shirring machines may be equipped with a heatingunit, such as illustrated in FIG. 6 whereby after a strand is shirred,severed, separated and doffed it may be transferred to a strand handlerunit of a shirring machine which can be programmed with a cycle forcompressing and removing the horn insertion end of the strand from theheating unit to form the end-dressing. Such operation can also beperformed manually.

Although the invention has been described in considerable detail withrespect to the preferred embodiments thereof, it will be apparent thatthe invention is capable of numerous modifications and variations tothose skilled in the art without departing from the spirit and scope ofthe invention, as defined in the appended claims.

What is claimed is:
 1. In a shirred strand of tubular food casing filmwherein said strand has on at least one terminal end thereof loose,unshirred or residual casing film, the improvement which comprises thestrand having an end-dressing at an affected terminal end, said dressingbeing formed from said loose, unshirred or residual casing film bycompressing said loose, unshirred or residual casing film against theterminal edge of the shirred strand while heating to a temperature belowthe fusion temperature of said film, said loose, unshirred or residualcasing material being secured to the terminal edge by ironing-onto saidedge without adhesion, whereby the ironed-on loose, unshirred orresidual casing material releases from said edge during filling.
 2. Thefood casing of claim 1 wherein the end opposite the dressed end has anend closure to prevent loss of food emulsion during filling.
 3. The foodcasing of claim 1 wherein the casing material is regenerated celluloseor collagen.